Dirigible bomb



R. D. WYCKOFF ET AL.

Aprii 5, 1949.

DIRIGIBLE BOMB 8 Sheets-Sheet 1 Filed May 31., 1946 flmwc nfwps RELPH D.WYCJKOFF JULIUS P. MOLNBR LOYAL 'D. P'ALMER G (JV C. BLEWETT April 1949-R. D. WYCKOFF ET AL 2,466,528

DIRIGIBLE BOMB Filed May 51; 1946 s Sheets-Sheet 2 N 111 FL ALPHnwvcxoFF JULIUS P. MOLNAR LOYAL D-PAJLMER GUY (LfiJJElWjECTT April 5,1949.

R. D. WYCKOFF ETAL DIRIGIBLE BOMB 8 Sheets-Sheet 3 Filed May 31. 1946gmtz/wboms RALPH D.WYCKOFF JULIUS F? MOLNAR 11 P LMER GUY c. BLEWE April1949' t R. D. WYCKOFF ET AL 2,466,528

DIRIGIBLE BOMB Filed May 31, 1946 8 Sheets-Sheet 4 SELF BALANCING 5 3102512 7 I51? {EQNNECIIQN RADIO RADIO 7 PULSE RUDDER TRANSMITTER g gwgg"415 RATCIR *Acrumrm A0 -RADIO RADIO TRANSMITTER RECEIVER OSCILLATOOSCILLATOR Fl. FR f [77% 'RUDDER g ACTUATOR '21 721? 72. u

glwucnfoos RALPH D. WYQKOFF JULIUS P. MOLNRR J- YAL D. PfiLMflR GUY C.BL EZTT April 5, 1949.

Filed May 31, 1946 R. D. WYCKOFF ETAL DIRIGIBLE BOMB 8 Sheets-Sheet 5.

April 5, 1949. R. D. WYCKOFF ET AL 2,466,528

' DIRIGIBLE BOMB Filed May 51, 1946 8 Sheets-Sheet "7 RBI- PH D. WYCKQFF$5. m; O 2- April 5, 1949;

D. WYCKOFF ETAL DIRIGIBLE. BOMB Filed May 31. 1946 8 Sheets-Sheet '8Patented Apr. 5, 19 49 DIBIGIBLE BOMB Ralph D. Wyckoif, Pittsburgh, Pa.,Julius 1'. Mol- Morris Plains, N. J and Loyal D. Palmer,

Oakmont, and Guy C. Blewett, Penn Township Allegheny County, 2a.,assignors to Gulf search & Development Company, Pa., a corporation ofDelaware Be: Pittsburgh,

Application May 31, 1946, Serial No. 673,374

2 Claims.

This invention relates to dirigible bombs and particularly to a remotelycontrolled so-called high angle bomb having a relatively stabletrajectory bearing a general similarity to that of a freely falling bombas distinguished from gllding bombs, for example, which approach thetarget at a low angle.

In order effectively to accomplish military bombing from aircraft, it isnecessary to have a high percentage of target hits. Numerous aimingtechniques have been employed to improve bombing accuracy and at thepresent time this has reached a fairly high state of development.

When a bomb is dropped so as to fall freely from a plane, variousfactors are known to effect its sideration of the known factorsinvolved, a certain amount of scattering occurs due to unpredictable anduncontrollable effects. Some of these effects are aerodynamic, somemechanical, and some atmospheric. I

It has been found desirable to steer an otherwise freely falling bomb soas to correct for inaccuracy in aiming and to correct for unforeseeableeffects encountered by the bomb in flight. In spite of the relativelyhigh terminal velocities attained by high-angle bombs, we have foundthat aerodynamic steering of such bombs in flight is both feasible andeffective. Bombing accuracy has thereby been improved considerably.

This invention concerns a form of steerable bomb remotely controlledfrom the bombing plane by radio. Inasmuch as the bomb-sight is dea hitanywhere along the length of the target becomes effective. y

In the making of a steerable high-angle bomb, a number of factors mustbe taken into account. Means for producing aerorynamic deflectingforces'must' be added to the bomb in the form of aerodynamic liftsurfaces. In addition, steering surfaces must be provided tomaintain theangle of attack of these surfaces required for the production ofdeflecting forces. In order to maintain the effective direction of thesteering controls, that is, to the right or left, it is necessary tostabilize the bomb against roll rotation.

Furthermore, stability in flight'mus't be maintained to avoid undueoscillation and gyration of the bomb. In addition, a number of practicalconsiderations are involved; namely, structural strength must besufficient to handle the ,aei 0 .dynamic forces required, the devicemust fit into already available component parts and preferably permitinterchangeability, and in addition space requirements should be reducedto a minimum and kept within that permitted on military aircraft.

Military requirements dictate that the bomb must be capable ofbeing-accurately guided to the desired target, such accuracy being ashigh as possible. By means of our invention an error smaller than 10 ft.may be attained for 15,000 ft. altitude. This requires a degree ofmaneuverability which, in turn, demands that the aerodynamic surfaces-develop suflicient lift forces to produce the required path deflection;that is, the maneuverability determines the lift which the bomb mustgenerate when yawed at a preferred maximum trim angle with respect toits lineof flight. The aerodynamic surfaces used to produce the requiredlift forces generally take the form of crossed tail fins. These may beprovided with movable flaps or tabs which are controlled to set up thenecessary attitude in flight.

Practical military requirements dictatefactors which are not allcompatible with the aerodynamic requirements- Space available onmilitary aircraft is limited, and the bomb must be carried in theinternal bomb bays of standard bombing. planes. Furthermore, the finsand controlling mechanism should desirably be capable of attachment tostandard bomb cases. In the dirigible bomb forming the subject of thisinvention,

all the necessary components are contained in a bombing plane.

cheeses the crossed-fin tail surfaces should be rotationally oriented inflight so that one pairv of co-planar fin surfaces lies in the plane ofthe trajectory and the other pair of fin surfaces are at right anglesthereto. Thus one may obtain rightleft rudder control by applyingrudders to the fins.

which lie in theplane ofthetrajectory. The

other fins may convenientlybeequipped with ailerons for maintaining rollorientation. If the bombs are carried in the bomb baysuch that thesesurfaces have this orientation, the bombs take upa maximum oi'space;that is, they do I not nest well in the bomb'bay. In the device formingthe subject of this invention, the bomb -may be carried in thebomb bayin a position which is rotated at an angle of 45 degrees. with v theabove, the bomb being'automatically brought into proper rollorientationafter it. leaves the plane'to. carry a larger number ofbombs.

The efiect'oftheimproved nesting .of'the bombs in the'bomb bay permitsthe of the proportional control radio receiving ap- Y Y paratus ofFlg. 9on the bomb;

transmitting apparatus on the plane which may f be'used forsimpleton-oif" control;

Flg.:13 is'a block diagram of the radio receivi ing "apparatus usedinthe bomb to: cooperatev v with the on-oil" control transmittingapparatus of Fig. 12;

- Fig. l4is a schematic electrical wiring diagram v v v v of the radiorelaycircuit used for the on-off" control;

Fig. 15'is a schematic electrical wiring diagram v v v v i of the rudderactuating servounit used for the. on-off? control;

It is an object of thisinvention to provide a remotely controlledhigh-angle bomb.

. Another object of this invention is to provide a remotely controlledhigh-angle bomb steerable in. azimuth after release. 1

Another object is to provide a remotely controlled high-angle; bomb.having a. unitary re motely steerable tail structure which isinterchangeable withthe tail structureof standard non-steerable bombs.

Another'object of thls'invention is to provide a remotely controlledhigh-angle bomb lof gr'eat maneuverability which may be steered inazimuth by means of a rudder. controlledin proportion to i thedesireddegree of control.

Another object ofthisinvention is to provide a remotely controlledhigh-angle stable bomb which may be steered in azimuth by. means of a asimple on-and-oif rudder control.

Another object of this invention is to provide a remote azimuthcontrolled high-angle bomb having a cruciform tail structure and whichmay be nested in the bombing plane to take up a minimum of space. r

These and other objects of the invention are attained through the designherein specified. Reference is made to the drawings forming a part ofthis specification, and in which Fig. 1 is a perspective view of thebomb provided with the novel tail assembly comprising this invention;

Fig. 2 is a perspective view of the tail structure removed from the bomband showing also the modeof mounting onthe bomb and construction detailsof the housing;

Figs. 3 and 4 are side and rear views, respectively, of the tailstructure showing for clarity only the rudder actuating mechanism;

Figs. 5 and 6 are side and rear views, respectively, of the tailstructure showing for clarity only the aileron actuating mechanism;

Fig. 7 is a longitudinal section through one of the aileron actuatingsolenoids showingthe manner in which the solenoid rotates the ailerontorque rod:

Fig. 8 is a schematic diagram of one form of radio transmittingapparatus on the plane which may be used for proportional control of therudders affecting the course of the bomb;

Fig. 9 is a block diagram of the radio receiving apparatus which may beused in the bomb to cooperate with the proportional control transmittingapparatus of Fig. 8;

Fig. 10 is a schematic electrical wiring diagram Fig. 16 is a schematicelectrical wiring diagram, v v v i of a gyro-aileron control mechanismwhich may 'be'usedto set up and maintain the proper roll orientation ofthe bomb; and

Fig.1? is a schematic electricalwiring diagram of the electricalequipment on the-bombshowing the electrical relation of the various:components.v Referenceis made to Fig. l which shows the bornbinvperspective view and to Fig 2 which shows parts of the tail structureseparated :forv

purpose of clarifying the assembly. A'war head A which mas/for examplabea standard 1,000-

pound demolition type bomb.:has attached to it a box-like tail member Icarrying the components used for controlling the flight path of thebomb. The front end of the box I'is attached tothe standard war head Athrough an adapter ring Hi, this ring having a central aperture ll (Fig.'2) which fits over the threaded extensionv Ila at the rear of the bomband is held in place by alocking nut lib in a conventional manner.

nut ilb being tightened by a spanner wrench inserted in spanner. holesHe. The adapter ring I0 is thus attached to the tail end of the war headA in the same manner as the standard nonsteerable tail fin. The outsidediameter of nut Ilb is smaller than the inside dimension of box I, sothat the latter may clear the nut when attached to adapter ring Ill. Therectangular box l and its associated assembly is attached to the adapterring II) by means of screws passing through holes 911 in flanges 9 intothreaded holes 91) in the ring [0. The entire assembly of box I is thusattached to a standard bomb in a simple manner.

The box I is preferably formed by suitably shaping four sheets of metal,the central portion 4 of each sheet forming a side of the box while theside portions 5 and 8 extend at angles of 45 degrees and together withthe parallel adjacent portions of the proximate sheet form the cruciformtail fins. The sheets are held together to form thebox l by means ofangle strips I welded to the inside corners of the structure andexternal fillets 8 are secured by welding or soldering beture byinsulating washers 20. The uppermost and the diametrically oppositecorners oi the dipole are left open-circuited by the use oi additionalinsulating washers aunder the bolt head Ila and the strut ends, thusforming the two sections of the dipole which are connected to a coaxiallead-in cable 43 passing through the uppermost fin to a radio receiverwhich will be described later and which is contained inside the box I.Alternatively for a higher frequency carrier only two struts, i9,visible in Fig. 2 may 22 is provided with stud 24 which engages-a i'ormthe complete'dipole, or any or all struts may be connected as a simple Tor L type antenna with the entire shell and bomb case acting as a groundmember.

A transverse partition 2a is welded into the box I in approximately itsmiddle and serves to impart additional rigidity to the box and alsoserves as a mounting for various actuating mechanisms and components tobe described later. The

rear end of box I is normally closed by a flat cover plate 2.

The rear cover plate 2 carries a flare 3. The purpose of the flare is topermit the bombarcier to easily visually observe the course of the bombafter it is released. The war head A having a customary fuze (not shown)and arming devices (not shown), and the flare 3, are well-known devicesand do not form a part of this invention a per se.

Movably attached to the trailing edge of each iln surface is a controlsurface such as i2 and 29. These are made of spaced metal sheetscontinuously bonded by welded at their edges and pivotally mounted bymeans of torque rods i3 and 39 extending therethrough. The manner bywhich control surfaces 12 and 29 are actuated through torque rods i3 and30 will be described later. Two of the control surfaces, such as l2, actas rudders and provide right and left steering control. The fins towhich rudders i2 are attached are automatically oriented substantiallyin the plane of the trajectory during most of the bombs fall, as will bedescribed later. The other two control surfaces, such as'29, may serveas ailerons which provide roll orientation in a manner also to bedescribed later. The rudder and ailerons are hinged along a line percent behind their leading edges in order to minimize the torquesnecessary to rotate them in a wind stream.

Rudders i2 are mounted on rods l3 journaled at the outer end in bearingsformed in extension pieces [4, these being welded to blocks l5 which mayhe slipped in between the two sheets forming the fin and held in placeby bolts 16 and IT. The

, inner mounting of rods i3 and its actuating mechanism is shown inFigs. 3 and 4. The inner end of the rod i3 extends through an aperturein the vertical corner brace l of the box and is aligned by bearing i3aformed in transverse plates i3c which are welded to angle strips l.Connected to the inner end of each rod i3 is a crank arm I3b having anarrow open slot 13d at its outer end. A servo mechanism engaging theouter end of this crank arm controls the attitude of the rudder i2attached to rod IS.

The manner by which the servo motor actuates the rudders i2 isillustrated in Figs. 3 and'4. A servo unit 2i having conventionalstep-down gearing with limiting and centering switches and crank 22, issuitably supported on a base 2 lb which may be bolted to the partition2a inside box I. The axis of crank 22 is substantially parallel to theaxis of torque rods Hi. The outer end of crank Cir driving link 26. Thedriving link 26 serves as a coupling link to couple the two ruddercranks lib together and with the servo'motor in a manner whicheliminates any binding due to slight misalignment. Driving link 26 maycomprise a rectangular bar bent into a U-shape and having bearin holeson its legs close to the bends, these bearingholes fitting over theextensions lie of of torque rods I3. Driving link 26 has at the outerend of its longer leg a narrow open slot engaged by stud 24 and at theouter end of its shorter lega stud 28. The longer leg also carries asimilar stud 28 similarly located, and studs 28 engage the open slot lidof both crank arms l3b, these parts bein disposed so that when movementtakes place the difference in swing is taken up by the stud slidingslightly in the slot. Studs 28 are mounted on eccentric adjustments sothat slight misalignments may be corrected. The angle of travel of themotor crank 22 from its neutral position is approximately i22 while thecorresponding angular travel of cranks l3b and hence of the rudders towhich they are connected is an approximate :15. Electrical actuation ofthe motor in servo unit 2| therefore will rotate both the rods l3 inunison and thereby deflect both the rudders i2 in the same direction.The electrical control of the motor and switches in unit 2i will bedescribed later.

The ailerons 29 are identical in appearance and I rods 30 extendingtherethrough and into the control box I at alternate corners to thosemounting the rudders I2, the outer and inner ends of rod 38 beingjournaled in a manner similar to rods is already described. The innerend of each rod i3 has secured thereto a crank 3| having an openterminal slot Ma. The crank arm 3| extends into an elongated opening inthe case of transverse pin 33 maintained in an elongated clearanceopening in the cylindrical solenoid core 33a. The solenoid is wound withindependent coils 34a, and 36b on each side of its central cross sectionso that selective energization will move the core longitudinally andhence cause rotation of the crank 3 l, rod 30, and aileron 29. Eachsolenoid is suitably mounted on a bracket 34c inside the control box i.The ends of the solenoid cores are of customary conical shape and thecore is returned to center by spring-pressed pins 35 located at each endof the solenoid casing.

To coordinate the operation of the two solenoids and to insuresimultaneous operation of the individual ailerons regardless of anyunbalanced aerodynamic torques on the two ailerons, the rods 30 aremechanically linked together. Each rod 30 has mounted thereon adjacentits crank arm 3| a bell crank 38, cranks 3| and 38 being securedtogether by a bolt and nut assembly 39, one member havingan elongatedhole whereby the angular relation between adjacent cranks 3i and 38 maybe adjusted. Bell crank 38 has a slot 38a which engages a terminal pin38b on a rectangular rockin beam 36, the beam 36 being mounted at itsmid-point on transverse rocker pin 36a.

' Rocker pin 36a is supported in yoke 36b which is aceasas beam 36 isrocked. The rocker beam 35 thus ties together the operation of the twoailerons so as to insure their simultaneous and coordinated operation.The solenoid coils are electrically so connected and their actionmechanically linked by rocking beam 36 so that the ailerons operate inopposite directions in order to produce the necessary roll torque tobring the bomb into proper roll orientation.

Radio control The bombardier in the plane may observe the course of thebomb after it is launched, the ignited tail flare 3, Figs. 1 and 2,being clearly discernible even in bright sunlight. It has been foundthat by visual observation, the bombardier may easily determine thedirection of deviation required to bring the bomb on target. Variousknown methods of transmitting the necessary signals to the bomb from aradio channel may be used, two such methods being described here by wayof example. The rudders for steering the bomb to left or right may beactuated by servomotor 2|, as previously stated, the energization ofthis servomotor' being controlled by the character of the radio signalreceived by the radio receiver within the bomb.

For best maneuverability it is desirable to provide a so-calledproportional control system in which the angular displacement of therudders on either side of their neutral position is correlated inproportional relation to the movement of the bombardiers control stick.In one embodiment to be described, the energization of the servomotor2|, which controls the attitude of the rudders, is controlled by thecharacter of pulses transmitted from the plane and received by the radioreceiver within the bomb. In this system regularly keyed pulses aretransmitted over the radio channel, the bombardier's control stickvarying the length of the carrier's pulses. Thus when the on time isequal (or of predetermined ratio) to the off time. neutral control ,isobtained. An increase in the off time and decrease in the on timeeffects control in one sense, whereas a decrease in the "ofi" time andincrease in the on time effects control in the opposite sense.

One form of this system is described with reference to Figs. 8, 9, and11. The regularly keyed pulses transmitted over the radio channel areintegrated in the radio receiver on the bomb. The carrier is keyed onand off, and when the time on" is roughly equal to the off time thesystem is in its neutral position. Control is ob-' tained by increasingor decreasing the on time relative to the off time. The manner in whichthe transmitter is keyed is illustrated diagrammatically in Fig. 8.Numeral 300 is a control stick pivoted at point 30l and returned to acenter position by springs 302. Connected to control stick 300 is link303 which moves insulating block 304 sliding horizontally in guides 305.Mounted on insulating block 304 are two contact springs 306 and 301,spring 30'l being equipped with an insulating follower 308 which bearsagainst eccentric disc 300. Eccentric 300 is driven by motor 3) at anominal speed of about 1000 R. P. M. Adjustment of the contact points306 and 301 is made such that the contact is closed approximatelythroughout half the revolution and open throughout approximately theother half of the revolution. The contacts are connected by wires 3 tothe keying circuit of radio transmitter 312 whose signal is radiatedfrom antenna 3l3 on the bombing plane. By this means an interruptedcarrier signal is transmitted, the relative length of on and "off"periods being under the control of lever 300 in the hand of thebombardier.

Fig. 9 shows the control equipment on the bomb. It comprises antenna 3Mwhich may be the dipole made up of struts I9 (Fig. 1 Connected to theantenna is a conventional superregenerative receiver 3l5 which togetherwith pulse integrator 3|6 supervises the position of the rudder actuator311 in a manner to be described. The rudder, actuated through a selfbalancing connection, finds its equilibrium position in a manner whichwill become evident by reference to Figs. 10 and 11.

Referring to Figs. 10 and 11, Fig. 10 shows a conventionalsuper-regenerative circuit employing however an unusual manner ofadjustment to avoid phase reversal in the square-topped output wave ofthe receiver. In the simplest type of super-regenerative circuit theoscillation of the detector produces the grid blocking which quenchesthe detector. This means that the detector grid is biased too near thecut off 'end of the characteristic curve of the tube. On strong signalthe detector changes from grid detection to plate detection. Since thesetwo types of detection are opposite in phase, a phase inversion of thereceived impulses results on changing from very, strong signals tonormal intensity. In applications of this circuit to remotely-controlledapparatus, as a radio-directed bomb, the latter must be operated over arange from a few feet to some thousands of feet from the transmittingantenna and the phase inversion described above would therefore impart afalse movement to the control surfaces of the bomb. Consequently, asimple super-regenerative circuit cannot be empioyed.

Beginning at the left of Fig. 10, a conventional radio frequencyamplifier using tube 350, which may for example be a type 9001, isconnected to the receiving antenna and to the detector tube 35L forexample a type 9002, through coils Lo and L4. The radio frequency stageis necessary due to the fact that the super-regenerative circuit iscritical to antenna loading and hence must be isolated from the antenna.The radio frequency stage also provides some additional signalamplification and minimizes reradiation iof the energy originating inthe oscillating detec- A separate "quench" oscillator utilizing tube352, for example a type 655, and appropriate coils L5 for the optimumquench frequency, (much lower than that of the detector circuitfrequency) is connected to the detector 3! to trigger the latter intooscillation. The quench oscillator 352 is capacitatively coupled byadjustable ca pacity 353 to the grid circuit of detector 35l andoperates to vary the detector grid voltage to cause the detector 35I tooscillate at a rate determined by the constants of the quench oscillatorcircuit. The adjustment of the detector circuit 35! is such that in theabsence of energy from the local oscillator there is no oscillation ofthe detector at signal frequency.

Tubes 354 and 355 of Fig. 10 may be of the type 6SN'7 and comprise anamplifier circuit of conventional resistance-coupled type butresistances and condensers having long-time constants are employed inorder to preserve the square-topped wave-form for which the receiver isparticularly designed. The wave-form is comedusa of regularly-keyedvoltage pulses, the

which moves the control surfaces on the bomb.

The square-topped voltage pulses from the resistance-coupled'amplifierare utilized as follows.

The amplified square-topped voltage pulses are applied to the grid ofthe first section 353 of a twin-triode vacuum tube. By using large inputvoltages the grid is driven between two limits,

the negative cut-off and saturation, and so the average voltage at theplate 331 of this section is determined within limits, by the pulselength. The average plate voltage is filtered by the resistance-capacitycircuit comprising condenser 333 and resistors 333 and is directlycoupled to pends upon the grid bias of tube 33L which in turn. dependson the pulse length applied to the input. In Fig. 10 the filament supplyis conventional and is omitted for clarity. Terminals 335 are connectedto voltages as shown on a conventional power supply.

When the relay is open, the motor 2| (Figs. 3 and 4) for moving therudder surface runs in one direction and when the relay closes, themotor goes in the opposite direction. Further details i0 direction ofrotation of the motor. The latter turn is governed by the energizationof relay 323 (Figs. 10 and 11). Limitswitches Hi and 322 are positionedto limit the maximum amplitude of rudder movement on either side of acentral position.

In the motor circuit of Fig. 11, it is apparent that when power isapplied tov the terminal 323,

{it energizes shunt field 323, the circuit returning to the groundthrough terminal 321 and wire 323. The 24 v. power also energizes fieldcoil 323 and wire 330 and it is apparent that energization of relay 323will cause the. motor armature 33| to rotate in one direction, whileenergization of relay 324 .will cause the motor to rotate in theopposite direction through reversal of the current flow of the armaturewith respect to the field winding as is well known. The return currentis .via wire 332, 333 to 321 and ground. The energization of relays 323and 324 is determined by the position of relay 323. when relay 320 isbalanced so that it chatters between its contacts, the motor armature33| remains at rest. However, if the relay 320.conta'cts 334, powerfiows from the 24 v. supply through field 323. wire 333, relay coil 323,limit switch 32L contact 334' to ground via wire 323. If relay 323contacts 333, current flows in a similar way through relay 324 and limitswitch 322 through contact 335 and wire 323 to ground. The

as to the operation of relay 323 will become ap parent in theexplanation of Fig. 11 to' follow. In order. that the rudders be held inanequilibrium position corresponding to the desired angle, 1. e., pulselength, the motor 2| rotates a high resistance rheostat 333 (Fig. 10)which is connected to the grid circuit of the relay tube 363 and in sodoing changes the bias on this tube. The rheostat 363 is mechanicallycoupled to motor 2| (Figs. 3 and 4) through connection 364 of .Fig. 10.(This connection is conventional and is not shown on Figs. 3 and 4).Electrical terminals 321, 334,335 connect to the rudder motor as shownin Fig. 11. Thus, the circuit responds essentially.

as an automatically balancing potentiometer, which measures avoltagethat can be controlled directly by varying the length of the pulsesapplied. By choosing the proper values for the circuit constants, themotor response can be made substantially a linear function of the pulselength over the range required.

The successful operation of this circuit depends on the existence ofsuific'ient A.-C. ripple in the grid voltage applied to the secondstage, so that the relay 320 in the plate circuit chatters near thebalance point. In this way diificulties with relay hysteresis areeliminated. The amplitude of the A.-C. ripple can be controlled by theR. C. constant of the filter circuit. For optimum operation theamplitude should be limited to a value which permits relay chatter onlywhen the motor is within a few degrees of the balance point. As

will be evident, the ripple amplitude required depends on the difierencebetweenthe pull-up and release threshold current of the relay.

Fig. 11 is a wiring diagram of the servomotor and reduction gear unit 2|which is connected to actuate the rudders. Devices of this character arewell known, being used extensively in aircraft I limit switches Hi and322 merely serve to open the relay circuit when an extreme position ofthe crank arm infeither direction is reached.-

trol of the rudders. In this system the rudders are either full on orfull on, and in the absence of control. return to neutral. Thebombardier applies left rudder or. right rudder as desired for a timewhich he estimates will correct the devialators having frequencies F1.and Fa, each modulating the transmitter 40 at its characteristic audiofrequency when its respective key'42 and 44 is pressed. The frequenciesF1. and Fa may conveniently for example be 475 and 1000 cycles/sec. Thusthe bombardier has two push buttons 42 and 44 which control theoscillators Fr. and Fa to modulate the radio wave transmitted to thebomb. The controlling radio wave therefore comprises a carrier frequencymodulated by an audio frequency appropriate to the direction ofdeviation which the bombardier desires to impart to the bomb.

Fig. 13 is a blockdiagram of one form of radio receiving equipmentcarried on the bomb and used for responding to the steering signals fromthe plane. Here 46 represents the dipole or other type antenna made upof the struts l3 (Figs. 1 and 2). Connected to the ends of the dipole isthe coaxial cable 43 (Fig. 1) leading to conventional radio receiver 41,including a demodulator which delivers audio signal to two filters L andR. These are narrow band-pass filters of known type and when anappropriate signal is received,

it is passed on by the agency of relays (which will 'be described later)to rudder actuator 2|, which in turn deflects the rudders I2 in theproper sense. In the above form of control here described, only "on-offcontrol is obtained, the rudders returning to neutral in the absenceofany audio signal. If the bombardier, for example, desires to applyleft rudder he may close contact 42, Fig. 12, and thereby modulate theradio signal at a frequency FL- The receiver 41 picks up this signal,and passes on a frequency F1. to the filters L and R. As the frequencyF1. may only pass through filter L. relay L is energized and there isapplied to the rudder actuator power to drive it and the rudders intothe leftwise position. If neither of the contacts 42 or 44 are closed bythe bombardier, the rudder actuator automatically returns to its neutralposition as described later.

The operation of relays L and R of Fig. 13 is shown by the wiringdiagram of Fig. 14 in which numerals I I3 and H4 represent the plateconnection of the last tube in the audio filters L and B, respectively.Each of the plates I I3, II4 are connected through a relay coil I I1 andI I8 to a common high potential terminal I2I leading to the radio platepowersupply on the 'bomb. Armature contact springs I22 and I23 arenormally connected to the righthand contact as shown in Fig. 14. Upontransmission of a signal. through the audio filter the center spring ofthe relay is drawn over to the lefthand contact. Thus if no steeringsignal is applied the relays will be in the position shown in Fig. 14.The circuit diagram shows how the contacts and springs are connected tothe terminals I28 to I32. Terminal I32 is connected to ground. TerminalI3I is connected to 24 v. power supply. If the bombardier applies asignal of a proper frequency to actuate the filter L (left), relay II1pulls contact I22 to the left. This grounds terminal I28 through leftcontact I22, wire I40, right contact I23 and wire I. At the same timethe ground on center connection I29 is broken at I22. Similarly, if thebombardier applies a signal to actuate the filter R (right) relay II8pulls contact I23 to the left. This grounds terminal I30 through leftcontact I23 and wire I4I, while at the same time the ground on centerconnection I29 is broken at I23. Keeping in mind that the application ofsteering signal merely grounds the appropriate terminal on the rudderactuating mechanism, we shallnow describe this mechanism.

Fig. 15 is a schematic wiring diagram of the ceived the actuating motorautomatically returns the rudder to the center position. Right ruddersignal moves the rudder to the extreme right positlon. etc. To assist inexecuting these movements,

the arm 22 of Figs. 3 and 4 operates through appropriate cams toswitches I52 and I53 of Fig. '15. Numeral I52 represents a limit switchmechanically so arranged that when the motor arm 22 reaches its extremeright position contact I52R. is mechanically opened. 0n the other handwhen the motor arm reaches its extreme left position contact I52L isopened. In all intermediate positions of the arm 22 both contacts I52Land I52R are closed. Another cam on arm 22 operates a centering switchI53. Contacts on this switch are so ar1:.nged that they are both openover a very small region at the center position. Contacts I53R and I53Lare closed, respectively, when the arm 22 is off center to the right orleft, respectively. Relay coils I10R and I10L when energized movecontacts "I, I12, I13 and I14 to the left. Contacts l1I, I12, I13 andI14 are returned to the right hand position by springs I15 when therelay coils are deenergized. Terminal I54 is connected to the 24 v.power supply. Terminal I55 is the ground connection and terminals I28.I29 and I30 go to the radio relay (Fig. 14) previously described.Bearing in mind the mechanical operation of switches I52 and I53 and ofrelays NOR and I10L, and the fact that radio control merely grounds thedesired terminals I28, I29 or I30, we shall now describe the operationof the actuating mechanism of Fig. 15.

We shall assume that the rudders are in a center position so that thecontacts I53L and R are both open, contacts I52L and R are both closed,such being the situation when no signal is applied. Upon the applicationof left rudder signal radio relay II1 (Fig. 14) will ground terminal I28(Figs. 14 and 15). Current then flows through the circuit of Fig. 15 asfollows: 24 v. current enters through wire I54, contacts I52L, wire I16,relay coil I10L to ground via wire I56. This holds contacts "I and I 12to the left and the current flows from wire I54, wire I11, wire I18,contact I13, contact I14, wire I19, wire I downward through motorarmature I50, wire I8I, wire I82, contact I 12L, wire I83, contact I1IL,wire I84 and wire I55 to ground. At the same time the current flows fromI54 through I11 and I18 to the motor field I5I, wire I85 and wire I55 toground. The motor subsequently rotates to push the rudders to the leftuntil the'left limit is reached, whereupon arm 22 (Figs. 3 and 4) openscontact I52L thereby releasing contacts "I and I12 to cut off the motor..The motor will remain in this position as long as left rudder signal isbeing applied; namely as long as terminal I28 is the only one-grounded.If, however,

through I54, contact I52R, wire I88, relay I10R,

wire I81, wire I88, contact I53L, wire I89 to ground. This closes relayI10R moving contacts I13 and I14 to the left. Current may now flowthrough the motor armature as follows: wire I34, wire I11. contact "I,wire I83, contact I12, wire I90, wire I8 I, upward through armature I50,wire I80, wire I92, contact I14L, wire I93, contact I13L. wire I85 andwire I 55120 ground. This causes right hand rotation of the motor untilthe center is reached whereupon contact I53L opens. This breaks thecircuit through relay I10R. releasing contacts I13 and I14 and shuttingoff the motor. The application of right rudder grounds terminal I30 andremoves the ground from terminal I 29 and the subsequent operation ofthe device is very similar to that when left rudder is applied, exceptthat direction of the current flow in the armature is such as to produceright hand rotation. If after the application of right rudder, thesteering signal is removed, the motor returns to center in essentiallythe same manner as above described. It the bombardier desires to do sohe may apply right rudder immediately after the .application of leftrudder or vice versa, in which ance may be connected across relay coilsI'IOR and I'IOL in order to reduce sparking and radio interference whencontacts open the relay energizing current.

Roll stabilization In order to maintain the bomb properly orientated sothat the right and left rudder controls remain identified, it isnecessary to provide a stabilizing mechanism actuating ailerons whichmaintain such roll orientation. Accidental rolling torques may beimparted to the bomb during its fall by accidental inequalities in thetail surfaces, or during launching, or may further de-- velop due toinequalities in the steering effect of the rudders. A gyroscopicstabilizer is employed consisting of a directional gyro, so mounted thatthe plane of rotation of the gyro wheel is in a vertical plane ofsymmetry of the bomb corresponding also with the plane of the trajectoryat launching. The gyro includes electrical connections to the aileronactuating solenoids so that if the bomb begins to roll in a clockwisedirection, for example, the ailerons will be moved simultaneously in adirection to produce a counterclockwise restoring torque on the bomb. Arateof-turn gyro is simultaneously mounted to reverse the position ofthe ailerons if the rate of rolling exceeds to per second. The aileronsare thus always at one extreme position or the other, producing slightroll of the bomb about vertical orientation at a rate that never exceeds10 per second. C

The construction of the gyro wheels and their mountings, per se, do notform the subject matter of this application. Examples are described,

in a patent application, Serial No. 543,168, filed July 1, 1944, by J.P. Molnar and A. Camvale, and also in an application, Serial No.639,686, filed January '7, 1946, by B. E. Warren. It will suffice hereto describe the electrical circuits controlled by the gyros, these beingshown in Fig. 16. The direction and rate-of-turn gyros described in theabove patent application of Molnar 8; Carnvale are coupled togetherinsuch manner that zero position on, the direction gyro varies with thedisplacement of the rate gyro and hence with the rolling of the bomb.The effect of this coupling as explained in the above-mentionedapplication is to permit a speed of rotation proportional to thedisplacement of the bomb from its equilibrium position and thismaterially improves the roll stability attained by the control.

In order to permit the bombing plane to carry a maximum number of bombs,it is highly desirable that they be nested in the bomb bay with theirtail fins 45 to the horizontal. The aileron controlling contactorstherefore have their neutral position rotated through 45 as indicated inFig. 16, so that there is initially applied to the bomb an'raileronefiect which remains until the bomb has rotated 45, thus placing therudders in and 6.

the cont'actor I00, Fig. 16, is'to open the'ground connection to relaycoil I00 at the equilibrium 0 position of the directional gyro.Contactor I09 opens the ground connection to relay I00 at an excessively large deviation of the rate gyro in one direction, and closesthe ground to relay I00 at an excessively large deviation ,of the rategyro in the other direction (i. e., when contactor I" is open). v

Fig. 16-is a detailed schematic diagram of the gyro unit, connectionsbeing made as shown.

After the bomb has been released, terminals I0 'and I5 connect to thepositive terminal of-the bombs battery, as will be described later, thussupplying power to the gyro motors 99 and 94 through radio frequencychoke 95 with condenser bypass to ground. Choke and condenser 90 serveas a filter to prevent commutator interference with other apparatus onthe bomb. Un-

caging solenoid 91 is powered from terminal ll,

and is energized on launching the bomb, as wil be described.

In Fig. 16, terminal center contacts 99 and 99 of a. relay whose coil isshown at I00. Contacts 98 and 99 are biased to connect to springs IM andI 02 when coil I00 is not energized. When relay I00 is energized,contacts 90 and 89 connect to springs I03 and I04. Relay I00 isenergized from connection I4 and controlled through contactors I05 andI09 mounted on the gyro gimbals in a manner described in theaforementioned Molnar and 'Carn-' 98 and 99 are provided to handle theaileron sole-v noid current without heating or sticking. Relay coil I00has resistor shunt III to prevent sparking at the gyro contacts and therelay contacts have relatively high resistance shunts II! to preventsparking on opening of theaileron solenoid circuit. Wires I6 and II fromthegyro unit connect to aileron'control solenoids 94a and-34b shown inFig. 7, the detailed operation of which has been described in connectionwith Figs. 5

Bomb controls Fig. 17 is a wiring diagram of the bomb and shows how thevarious components are interconnected. The components illustrated arethose for on-oil?" radio control, but the alternative proportionalcontrol may easily be substituted with obvious minor changes in thecircuits to conform with the detailed diagrams previously explained. 1

Referring to Fig. 17, the bomb is equipped with a so-called kick-offplug 5|. All connections and components located below this kick-oil plugare contained in the tail member I (Figs. 1 and 2) of the bomb.Connections above plug 5| are on the bombing plane, plug 5| being at theend of a short length of four-'wire cable which pulls the plug SI outafter the bomb has moved away a few feet. The four connections 52, 53,54.55 on the plane serve certain purposes before the bomb is released.Asthe bomb drops away, the connections to these wires are severed andthereafter the bomb operates on its own as a self-contained I4 suppliespower to the 16) to uncage the gyro at release.

unit Wire 54 connects directly to the ships ground and serves as anelectrical ground before release. Wire 55 connects to the customaryelectrical bomb release mechanism on the ship and serves to uncage thedirectional gyro when'the bomb release mechanism is actuated by thebombardier. An electrical impulse from the release mechanism is impartedthrough wire 55 to perform this function as will be described later.Wire 53 is connected through switch 55 to 4 volt ship's power supply,this connection serving to supply power to various components of thebomb previous to its release so that all parts will be in operatingcondition when released. Switch 55 is normally closed a short timebefore release.

Wire 52 connects through switch 51 to the +24 v. ships power and ser esthe purpose of arming the tail flare 3 (Figs. 1 and 2). This is a safetymechanism to prevent premature operation of the flare. The four wires52, 53, 54, 55 are severed at contacts 52', 53', 54, 55 when thekick-off plug pulls out on release of the bomb, and thereafter thesprings of a kick-off switch indicated generally by numeral 58 makeother connections as shown. Mechanical interconnections between contactsprings are indicated by arms 59 and 60 which are made of insulatingmaterial.

Considering now the operation of various components on the bomb itself,these will be described separately. Flare 3 connects through wire BI toa thermal trip relay 52. The thermal release 63 is connected by the wire200 to contact 52'. Movable contact 64 is grounded through wire 65. WireGI is thus seen to be open until the bombardier closes flare armingswitch 51, whereupon thermal unit 63 burns out, permitting contact 54 toconnect to wire SI, grounding one side of the flare. The otherconnection of the flare made through wire 66 connects through currentlimiting resistor 61 to spring 68 of the kick-off switch. When thekick-off plug pulls out on release, spring 68 connects to spring 69 andis thereby connected via wires 'II and I2 to the 24 v. battery Icontained in the bomb. The negative terminal of battery I0 is groundedon the bomb. Thus the bombardier may arm the flare previous to release,and on release the severing of the kickoff plug closes the above circuitand the battery power ignites the flare fuse. A time-delay fuse allowsthe bomb approximately eight secondss drop before the flare ignites.

As previously stated, aileron control to maintain roll orientation ofthe bomb is obtained through the use of a free or directional gyrospinning in the plane of the trajectory. An auxiliary rate-of-turn gyromaintained in the same plane provides a rate-controlling mechanism.These two gyros properly coupled cooperate to prevent excessive rolloscillation of the bomb. The gyro unit itself forms the subject matterof copending application Serial No. 543,168 by Molnar and Carnvale andis indicated generally by numeral 12. Five wires l4, 15, I8, 11 and areconnected to the gyro unit whose internal circuit is shown in Fig. 16.Wire ll connects through spring 10 to contact 55' on the kick-01f plugand via wire 55 to the bomb release mechanism. An electrical impulsefrom the release mechanism is thus transmitted to wire 14 to theuncaglng solenoid 9'! (Fig. In order to make sure that the gyro doesuncage properly, spring I9 connects with spring 8| after the kickofl'plug is pulled and' this serves to connect wire 14 through spring I9,spring 9|, and wire I2 to the bomb's battery 10 to eflectively actuatethe gyro uncaging mechanism.

Wire I5 from the gyro motors (Fig. 16) is seen to connect throughcurrent limiting resistor 00 and wire BI and spring 82, thence throughcontact 53' and wire 53 to the bombardiers warm-up switch 55. Thus thebombardier may, before release, set the gyros irrmotion. Subsequent torelease, that is, when connection 53' has been broken, power to wire 15is supplied through wire 03 and spring 84 connecting to spring 85,thence via wire 86 and wire I2 to the battery 10 on the bomb. One mayalso note at this point that warm-up switch 56 leading through wire 53,contact 53 spring 02, wire BI, and rectifier 81, wire 88. wire 86, wire12, supplies ships power to maintain the 24 v. battery on the bomb fullycharged.

Wires l8 and 11 from the gyro unit connect via wires 89 and 90 toaileron control solenoids 9| and 92, shown also as 34a and 34b in Fig.'1, the detailed operation of which has been described in connectionwith Figs. 5, 6 and 7. Wire 18 serves as a ground for the gyro unit.Wire I01 serves as a ground return for the aileron control solenoidsthrough springs I08 and I09 and wire IIO after the bomb is released.Thus the aileron control solenoids cannot be energized except afterrelease from the bomb bay.

Returning to Fig. 17, it is seen that wire 15 connects to wire 89 andenergizes solenoid 82, current returning toground via wire I01, springI00, spring I09, and wire IIO. Wire 11 leads through wire 90 andclockwise solenoid coil 9| and to ground through wire I01, spring I08,spring I00, and wire I I0. Thus, it is seen that the gyro unit controlsthe operation of either clockwise aileron solenoid 9| 0rcounterclockwise aileron solenoid 92, in accordance with the previouslygiven explanation of Fig. 16. I

Referring again to Fig. 1'7, the radio equipment on the bomb is showngenerally by numeral I30 receiving itssignals from antenna 46. Radiounit I34 comprises a receiver and the necessary rudder control relays.In the case of simple on-on! control, unit I34 comprises a receiver 41,filter L,

relay L, filter R and relay R all shown in Fig. 13,

the operation of the relays having been explained in connection withFig. 14. Thus connection I32 goes to ground via wire I31. For operatingthe radio after release of the bomb and consequent removal of thekick-off plug, terminal I3I is supplied with 24 v. power through wiresI82 and 08, springs 84 and 05, wires and I2. Prior to release and whilethe warm-up switch 56 is closed the radio receiver, is supplied by ships+24 v. power through wire 53, contact 5!. spring 02, current limitingresistor 00, wires I02 and Ill. The 24 volt side is via ground in thereceiver to bomb case and via wire III, spring I00, contact 54' and wire54 to the aircraft ground connection. Thus the radio receiver is warmedup and in operating condition prior to release of the bomb. TerminalsI28, I25, and I30 are connected to the rudder actuator. The actuatoritself has been described in connection with Fig. 15, and the radio'equipmentserves by means of its relays to apply a ground to theappropriate connection desired. In theabsence of a control signal,terminal I29 is grounded and rudders arein center position Thus, forright rudder, the radio apparatus grounds terminal I30, at the same timeopening the ground on centering terminal I29. Similarly, for leftrudder, terminal I20 is grounded and the ground on I29 is opened. Theseconnections are accomplished by the relay circuit already described inFigs. 14 and 15.

The rudder actuating mechanism is indicated in Fig. 1'7 by numerals I60.This mechanism is powered with 24 v. power from the bomb battery througha circuit as follows: starting from battery 10, through wire 12, wire86, spring 85, spring 84, wire 83, wire I62, wire I63 to the rudderactuator. A ground connection is obtained 'through wire I68 and I31. Theother three terminals of the actuating mechanism go to radio terminalsI28, I29, I30 and the direction of rotation of the rudder actuatingmotor is controlled as previously explained with reference to Fig. 15.Having thus described our invention in detail and the manner in which itaccomplishesits objects, it is apparent that various changes andmodifications in the details may be made by those skilled in the art andwe do not mean to be limited in the controls to the particularembodiments illustrated. Furthermore, our invention may be applied to adirigible bomb of any type or size and is not limited to thedemolition-type bomb herein suggested. It may furthermore be used in thebombing of elongated targets which are moving as well as stationarytargets.

What we claim as our invention is:

l. A dirigible missile comprising a war head, a unitary tail structure,cruciform aerodynamic control surfaces fixedly mounted on said tailstructure, electrically insulated struts extending between said controlsurfaces and serving as a radio antenna, aerodynamic steering surfacesoperably mounted onthe trailing edge of said control surfaces,meanscontained in said tail structure operating one pair ofdiametrically opposite steering surfaces as rudders which place themissileinto an attitude of yaw so that the associated control surfacesmay produce forces deflecting the path of the missile, means containedin said tail structure receiving and transducing a' radio signal, meanscontained in said tail structure controlling the rudder deflectionproportional to the deflection of the control stick In the controllingaircraft, means contained in said tail structure operating the otherpair of diametrically opposite steering surfaces as ailerons tending toaxially rotate the missile, and gyroscopic means in said tail structurecontrolling said aileron operating means so that resulting aileronaction maintains the missiles rotational orientation such that therudders li'e substantially in a vertical plane.

2. A dirigible missile comprising a war head, a unitary tail structure,cruciform aerodynamic control surfaces fixedly mounted on said tailstructure, electrically insulated struts extending between said controlsurfaces and serving as a radio antenna, aerodynamic steering surfacesoperably mounted on the trailing edge of said control surfaces, meanscontained in said tail structure operating one pair of diametricallyopposite steering surfaces as rudders which place the missile into anattitude of yaw so that the associated control surfaces may produceforces deflecting the path of the missile, means contained in said tailstructure receiving and transducing a radio signal, means contained insaid tail structure controlling the rudder operating means insuch mannerthat the rudders are urged into their extreme steering positions inresponse to the frequency of modulation of the received such that therudders radio signal and are urged into neutral position upon theabsence of modulation of the received radio signal, means contained insaid tail structure operating the other pair of diametrically oppositesteering surfaces as ailerons tending to axially rotate the missile, andgyroscopic means in said tail structure controlling said aileronoperating means so that resulting aileron action maintains the missilesrotational orientation lie substantially in a vertical plane.

RALPH D; WYCKOFF. JULIUS P. MOLNAR. LOYAL D. PALMER. GUY C. BLEWETT.

REFERENCES CITED The following references are of record in the fi1e ofthis patent:

UNITED STATES PATENTS Number Name Date 708,411 Semple Sept. 2, 19021,537,713 Sperry May 12, 1925 1,890,175 Brandt Dec. 6, 1932 2,165,800Koch July 11, 1939 2,425,558 Ohlendorf Aug. 12, 1947

